SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c8bd1f9077b86da4c6e48fc95f724d5d3344bd3951b081d4ac9e566d84f88a6' 
  AND token = 'KClirpYWuRF1GJILrBmW/NLK5vgooAofh1J5yJZbhWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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