SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d85f99528cb0167aef706b807889b01fe0f88f40f2d9c9cfc17c474943e0873' 
  AND token = 'k+/wSNSYg8zEJ1oEl1UrO4caVQwLpRMmJKiPhnHGqW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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