SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e830c069553f7796d0d592167c0e203dfacd81122223e31377c19116e5056775' 
  AND token = 'I3bCXzyxqvpwm4Ww0CsJeztRZ0t+mRvStbMGhNgy7+M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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