SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2993f22a7da34b617086ad96b6d94aa70bca275228b5afdc80b6efdf9773fbdf' 
  AND token = 'cMvODOeCJ+mPi3npPtlujqn1Fy2smCcHwwsuGixU0mE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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