SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f6ee71c128fef8c4f7c9650cec0cfeb0094a3a88e9ea8981628be23b1056bc0' 
  AND token = 'UaoSHZiZKyQ8BYnkVCP0Sf2R2KsPrGa0xKfPRjRHlXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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