SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45f2a63654d85d474311d7ce3eeca66932960edb651ac85d5e4d360ae86496be' 
  AND token = 'qOGQt1z9nVbWxUKUhx48nbdVNXxMpQwA5hcnxaEbM98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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