SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e54f219ce0f5e746ee10a6ec2a8fc9faebac7503d4a6a641565f0ddff0aef8c1' 
  AND token = '+D83YYiK78zTZPUAhiao2pi1FoFN9gfCI6JGR7oFmAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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