SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ceb4cba1fddd60d963514703988ded73fb289904b5af6e26159e4639052be141' 
  AND token = 'MEuP/g0P4wGthZgigmABBef12E08UhC8vb0Q90Ml0Yc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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