SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8688b667f67527bedd8a9b4369855cbc2074acb930be4d181e6a1e91402fca60' 
  AND token = 'weY5Agf8gxkqzPQbuLEhIWTymeiLNiDDh8vDq2FDEnA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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