SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7eacc418a09711ed6b2357542343375d2b945956b1d4ef3f3f0ec576659a559e' 
  AND token = 'veoV/OgPEp3jLig4zTW2fbMGlMV3nq88JT532YayTxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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