SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0eafe98b3d39dcb34c7f16535918f6f26ee31c6a1c39c6792e24af60b3c3325' 
  AND token = '90KodL8XDFJSrmFulUTZUvLI+ZBOeXzPNkCM8cVETfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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