SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0460e616b1ebfe8ce155595d05a98f482644d449dd195f12e4af4f0bc06d82ad' 
  AND token = 'PSgiFO/S8UOrApe7Kocn7vDIN3qL4/bvZD9hznVIBzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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