SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c8fe7271a390a691e763ac2c32df58790bf2b827554c4425811f84332f8d318' 
  AND token = 'PQjYRjFZDI/CfrhsUAOyUH/IOGEuJ7oHzH+JjCZbEYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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