SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c081dea06df16b8dc4ba075df88291054a387dc9b25fa669ed82723c94fd15b' 
  AND token = 'xomXZjfbX+bHHfJnudEhHIDyWdM3bsfo+Oq2g4m75pY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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