SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '687fbcf10a9cfb3b7de16596948edbff85f01cd4a32b1a82887b277e0b7501bb' 
  AND token = 'bjXr7IVMYZZuvmwI9kLpoCSPQ5pCaG5uzJHsEdjHfwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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