SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cef4ce8db2661596cefcc19701625873b66312591184c3c5a54801d5fbac32d2' 
  AND token = 'dj6SocmXsgd671rd6LsBKSYftXvSavb1tKoXRhSYC+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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