SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5684368357799d3e3f71746f14392f9c1af9426d686603e205dac8cc4ea5ace' 
  AND token = 'jUN7ya34qHhBZJG24Dgy8CFMYZkE51FSDilN+IPYCTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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