SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ef853890b85e3d2ebd44d224e1e3c406ce3dad097c4590749bed09850ac87e7' 
  AND token = 'awDBhG6Y8P5TIFcqODDuvP1AhoBMWmjNsCeDADPX7yQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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