SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7543e4502b3dd77fe7bc9cdd131b08e3348e039fa5bf55af8f47b19bee0b82f' 
  AND token = 'W6DcgTf471bP4mjZZJpJy9vReN5gt+P+6MURevBD1NU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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