SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c87e1867b342fa1aaffdf416835b89fa17991d33787fa9b552eaeb71a480252' 
  AND token = 'zLycYgXbHbYp1GKCW+xMfCA9ei1AE0rxYMPOPE8BPJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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