SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a3487b00b0742717c22a53a1966afc41d78b56a0e7159755e8b57fea764033a' 
  AND token = '4iMH0/Z4iAOR8usgvXGbGAp2jcBvfBlS/nPHVIA6SHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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