SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '892e47cdd512869a04229b359ceda5bafae6b2d4eed280f2049f9bdb21c87af4' 
  AND token = 'rFq2Bhoq4kxJPqPH6b+A9Np4ygRYHw3C7pgZNdYRZEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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