SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f38c4aba26eeedfc1a1b1b6493da76337b071418ffc020c029ad0ab526bb4b1f' 
  AND token = 'gsXuUOp5S4wgXGJEGKfGn/7Y14ygcGJzSBz9MHYc5u4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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