SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bed5dcf4bf862a5eea03ee9726e78802e06cb154699d0addcb8c5948cbb51980' 
  AND token = 'vca0A7zIr2Jgs44VkW3Bcw+VlYyLEcgE87yBBYNJrHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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