SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c6961569fea774b13119513d72dc6fcefd0a7424b75b08bdf55e1390e1634f1' 
  AND token = 'lrhvMFGi5RCX6qzsvBc5aSaM4PTHg1ytQ2/Y+OVseec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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