SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94a820636b223ecbe93124c341a0b8dbf46134db3d530cfbe24009bfbc729c82' 
  AND token = 'Ru1ivN6+oG0ABjbLrGYhgtqF/pQBb8VTLtuEZopwAq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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