SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c8d49bf9debe03184bc1de5207579e4c5b19aa56e5e62533d678014f8a94f9d' 
  AND token = 'Rv+2bFrgDl+v7wBh86k2exTLRG0poALUZKlB/TeCmls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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