SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6e2a1a635c1973b4173edd573a6a556ded221dddde745618378cc1239cf7566' 
  AND token = 'AEBg5eIC4RgmGJPMEBow1TQP9vtv4NSy8Sxy8HRJeuc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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