SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19dd96e970217bd20e853ba7c5385004e8e246d2a385fc8a55f2d53cf70b63d5' 
  AND token = '8kknR1ITxYVHpg6Q+W3KowTo5SCFhg+wPhdduri/jQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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