SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8eccf9e111472b1b8f7bb8087f3badec65787f150769b666784325a4cc509b47' 
  AND token = 'psrqMFkkQbHrWrxw+dCYleXj4RsgSKuB6dktLuxTrLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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