SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d35464242c498685a82a1063ab6c58a5f01dab824421019e0fec8f3775ad352' 
  AND token = 'LZx0tpCvy6IRN8WqzDksc8tVDRrtomvrq3/Oxmiyp6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}