SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10c514aa287a8fd33fcbf036f44d65b5644d320501dc4c85065bde180e5778f3' 
  AND token = '5xKK4mdtgTGZOMBJDJ2TGU7NE84Q6XqjD+GEnvAT/J4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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