SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9d8dc990c6cdc4345ba36479a86919d738ba57f44760b25a9b0e46ac09478da' 
  AND token = '4WiQS4ZQTBObcBPdXm9yGtdASa361oGMxvUzH609Pc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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