SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4459d6b46037d516558fc98696704f694aa61b7bd8bd742536b4fbfcc0f5cbe7' 
  AND token = 'p5kUZJ3IF2kDS5j6sLbm5gyTxklM7dLrFIezBEfE+fE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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