SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3af6664dee299fa0d05c6e8e1e2264dce7cec355717f42cbda51d4076d3e4528' 
  AND token = 'vsia5wabFYC6xFHB0O+Mb8U6pzsNFUtk3bGbhTs2yQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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