SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b12e6c09f642a2f005510de7ea9f252a3198c7187cbbc74c7219341d226abecd' 
  AND token = 'czmHD9VMYiWWrQyzeCmyvH/W5BUdy71DAUbhinz9k00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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