SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd558370efef5bbe0d67fa0913d59238de75996424bd27b248bb8ef9d4a0f9c83' 
  AND token = '2n/ZzOVMVSMFfHzWGhkHCag0nAio07Wcsg7OvdaTZbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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