SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71fef8e18d1dd95f8dc4e5e76fdc49756b670b273864b122be8d3ddd152a8ff1' 
  AND token = 'BvGzzqFAEwu2aBrfsPI2pRHY+ltuzRMQdgPHOqhXF/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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