SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74a142f9c45008f990a885330225139e49b9249ea949e60c97fc67c5734e535e' 
  AND token = 'tRjnaS1SzkHNSfU3XPwuxLNe84Dsv9CKDIKBDeJo5fA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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