SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a58599e971845328e51e394560bd4d52d4afcfb2d77167f7275e3e16d0a40d5' 
  AND token = 'tLCax+34qVZgXS8yLv+KbBVSTmJ55q0vPhyoWg6AQ6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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