SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99399b617025ed20062825e23c99b205f9cd4652068f0ac034c63aae2f06bcb2' 
  AND token = 'I3IRuoQIBh8p5PJf8gRM+vdymToUZfg8mF2xO6+EEUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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