SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7f7b2116a1a86bf0b6762e82842aeb91b882564c17bafd5904f543bafa693b1' 
  AND token = 'sAedV6RF1DFWWLIMR+1nxOors/9/+3qCPAQXuYQwqT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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