SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9642c46800c63380d629459992fed34c2ce0643b8d20d80ff5e2dcb1230d90af' 
  AND token = '1BEMhh0NEsMitrU16dx+WTAkrt4aLtW8egNLN2ljiPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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