SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8e34332fcfd46554f1a4a9ac6ce2609d3561cf417b0e5c2a169eaf0b7fa7baa' 
  AND token = 'ikRMBXDEs4o6scFuuUYb/Vy0HMgwu9igc4UcN/dTSIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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