SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57bb93e38af1dd513da9524d2f9c1d274064f0af9baa8c7f5fb5dc43687d5616' 
  AND token = 'fgAR1yEWzuXnoZrNOBI9axCJlpZKtPdljcnq4aqoTGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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