SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a4990213474523847c6d5a4a3f2efec25da6437c60a5249c582fc979ea11c33' 
  AND token = '2FT15bFzKMSYdhzQQsScRvI38FHiqkPROI34YelHt+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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