SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1781a9dfea091f9c587496920c4e11a1b1d6be07bef0c6229e4d0753b76f719' 
  AND token = 'Cm8PkHCa3ULUxmnpZCL+DPrGuhY8LqBgsRBIp+eAyqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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