SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19abc7c87b17e863b730ef8632fa3b6056f30d21618a0093f3c355437611701c' 
  AND token = 'T/VgtmsSk3y3ZNV1MrjNkJMdUeLRwKiK+RuWrouoHss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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