SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6620da12120158db13ecf87883cd7510a6e2a0d1d264f355ae2e8ee549409006' 
  AND token = 'oOF4KKyZQCNRXlEeuScodySlXGFUKF6moduvVdfOgsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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