SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e34d6854f2a1ef7d7056418c250389fc18604c69417f4df3ed230ee29f6a09b' 
  AND token = '7nfYl1mBcpAYGfdW6RbmHm70J9BLN6rPWhJ4FAqguus=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}