SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1370216636881243edf2825142a18dee2822e2154069c5d465045a280bcbc2d' 
  AND token = 'uh504+RpM1TcQ+OxdAS/nMZRNP3uy9BqUstryBy/6UU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}