SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3d87d45e06ba96f64b309f18976ccd27f0fc9b732ba52869d9d2e35f0a3dca9' 
  AND token = 'jQgGOhRLZ4kz/8DFIFjJCFamB5JogOn8QsSs0uH8kJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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