SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c771674fd560ee78c909c7b9447afda625d8a9dd022109eead4e2a0eeeac5f4d' 
  AND token = 'Rt23z0rfRHX7WTOY8iZG2LmV1qJyTc/UUKq83M4OhHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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