SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7830b5b2b9b7c3b29b9d6e34d6c2361ff7f9aa7d2f066d94d11fae81e51982a5' 
  AND token = 'ErHbspvwFBxUzHExDEZeYV/cneSXTDxwZ5uvxbMF/Go=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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