SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc763cb10cb468f374bb54b4642771a7b0d83f90f435ce826290536280964a3d' 
  AND token = 'fi9xCR7MH+j5QOeXUU0zwwAHrt8hahj0fGFkZEKxXAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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