SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '877d09a97c562e0b14871e33b58c7eb567f282a374f8c18df34ddb8108357778' 
  AND token = 'z7+l7hY+EXE04cdvjGz0gHJY8OS4apgCiGKOHijK9Z4=' 
  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"
    }
  }
}