SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f4365c8d3583510eae5c6c24e2d91ed4aa6db461e6a0b278abcc4c09b0fb56c' 
  AND token = 'LrRHuf7Gf9gk3bbYpsYmH/RY3YZETrcyxQVCFIrLKO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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