SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36b42d3c613073b0a95829467c3a1dd7a80471f067f957723877c1d8e3fb0187' 
  AND token = '6IzFDTspav4vOKgHHQ/HFfQq1HYU+T65jHro0/sPZEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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