SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '417c916e8059ea13e4f59482c84ca8d53c991e64924dc4e8103584553c786615' 
  AND token = 'wFQcOdFl640frXK8sY5fTjf/F3JgTIKx3jlzOEAefyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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