SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4627d94f6ff54421b976228e9fac603d211b60e817ca4dc6f364605e9b3eb576' 
  AND token = 'HofjVzM7lcNJCKJe9x6FkjAkEsRYW2xpptELugLVKEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}