SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c4f3ae40106c41534beff8486c410afdc9c9c53a937075fe61c65720214ad02' 
  AND token = 'rjT436s4jj7jv7aUag2rIcmKgZ8Tn4f/TO1n4m/Cgi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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