SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f406ea2107de627ec63bbef00bd1bbe7fd3659822720d3a068a94e649ab3bd78' 
  AND token = 'lmwiduqvdGYNJzVPiyeiXXtvGOBEjoMVvnjKh/fE5QM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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