SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c586e9041a6519f6342f35a15844e1da1928ec58d82ec4b971a91ebda92008e' 
  AND token = 'Ud3tN8hXFN9jgrshciwtgKNSPhqkhnss7NhQsZTAgAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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